Influenza activity in Switzerland is set to intensify further. The Federal Office of Public Health (FOPH) says the 2025–26 flu season is shaping up to be a severe one, with the viral peak yet to be reached.
Last week, 33.5 laboratory-confirmed flu cases per 100,000 inhabitants were reported. That figure is 4.6% lower than the previous week, but officials caution against reading too much into the decline.
Reporting delays over the year-end holidays have temporarily distorted the data, a FOPH spokesman said. Meanwhile, after dipping during the festive period, outpatient consultations for acute respiratory infections are rising again.
New strains in circulation
The dominant influenza viruses currently detected are the A(H3N2) and A(H1N1)pdm09 subtypes. Preliminary analyses by the FOPH also point to the circulation of a new sub-clade of H3N2. According to the European Centre for Disease Prevention and Control, there is so far no evidence that infections linked to this genetic subgroup are more severe.
Regionally, incidence rates are highest in Schaffhausen, Basel-Stadt and Jura, and lowest in Appenzell Ausserrhoden, Obwalden and Uri. Geneva and Fribourg have been relatively spared, while rates are somewhat higher in Vaud, Valais and Neuchâtel.
RSV on the rise, Covid recedes
Respiratory syncytial virus (RSV) is also spreading widely. Viral loads detected in wastewater have continued to climb in many regions, tracking closely last winter’s pattern, the FOPH said.
Covid-19, by contrast, peaked last autumn. Infection numbers have been edging down since, and are broadly in line with those recorded a year ago.
More on this:
FOPH flu statistics (in French) – Take a 5 minute French test now
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